CORS is a minefield. It doesn't help that the RFC is incredibly dense. I may be totally missing something, but I've repeatedly wondered though if CORS still has its place in times of SPAs that exclusively use xhr + javascript + some sort of auth token talking to a REST API?

Consider this argument: CORS basically ensures that browser and servers cooperate to protect end users from a "smart" user agent that happily throws around cookies and/or auth tokens. Remove cookies and basic auth headers, what's the point of CORS?

Happy to hear thoughts from folks more knowledgeable in web security than me. If not, let's please get together to propose an RFC for the CORS-GTFO header (a server header indicating that a browser does not have to do wasteful preflights etc.)